coreutils: missing integration test suite for coreutils binary

[ChrisDryden]

Came across this in two separate PR's where it would be good to have integration tests for the coreutils binary but we have not set that up yet. In the PR where the list of the utilities is sorted in build.rs it would be good to have a regression test for that behavior. #10820 The other use case is regression tests for the fixes in the get_vs_opts gnu test.

[oech3]

Note that we already have env -a test against coreutils (hijack argv[0]). So we could use env -a coreutils env --list at Rust test for env.

coreutils/tests/by-util/test_env.rs

Lines 726 to 739 in 194d980

	fn test_env_overwrite_arg0() {
	let ts = TestScenario::new(util_name!());
	let bin = ts.bin_path.clone();
	ts.ucmd()
	.args(&["--argv0", "echo"])
	.arg(&bin)
	.args(&["-n", "hello", "world!"])
	.succeeds()
	.stdout_is("hello world!")
	.stderr_is("");
	ts.ucmd()

One of a problem is output of --list is not frozen...

[oech3]

It seems tests for coreutils itself is done at https://github.com/uutils/coreutils/tree/main/tests (because num of tests are few? idw).